Seal or fluid barrier using strands

ABSTRACT

The present invention provides for a seal or barrier comprising strands that are woven or wrapped in an overlapping manner such as, for example, helical or circumferential patterns.

This application is a continuation of application Ser. No. 10/904,722filed on Nov. 24, 2004, incorporated herein by reference.

BACKGROUND

It is often desirable to block or restrict the flow of fluids or solidparticulates in a well. For example, a seal between a downhole tool anda well casing such as is commonly found in a packer may be used toprevent or restrict fluid flow between formations. A tool may alsorequire a seal or fluid barrier within the internal structure of thetool, say between an inner mandrel and an outer housing.

In the prior art, braided rope packing has been used to form a sealelement or barrier for downhole tools, particularly in valves. Thepacking is cut and wrapped around a mandrel in a mold and pressed into adesired shape. The rope packing holds that shape while being installedover a mandrel or into a tool. Compressing the braided rope packingcreates a seal or barrier. Elastomers, cast or milled to a desiredshape, have also been used to form a seal element or barrier in downholetools.

SUMMARY

The present invention provides for a seal or barrier comprising strandsthat are woven or wrapped in an overlapping manner such as, for example,helical or circumferential patterns.

Advantages and other features of the invention will become apparent fromthe following description, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a plan view of a seal or fluid/solids barrier constructed inaccordance with the present invention.

DETAILED DESCRIPTION

Referring to FIG. 1, a seal or fluid barrier 10 comprises strands 12woven in a overlapping or mesh pattern. The pattern may be helical,circumferential, orthogonal, or some other arrangement of strands 12.Strands 12 are preferably metal, but could be some other natural orsynthetic material such as nylon or fabric with apolytetrafluoroethylene laminate (e.g., GORE-TEX®). Strands 12 may becircular or angular in cross-section and may be of various lengths.Variations in the strand cross-sections and lengths can be used to meetparticular performance objectives. Strands 12 may be impregnated orcoated with an elastomer or other conformable material to form acomposite seal or barrier 10. In an alternative embodiment, in place ofwoven strands, smaller, shorter strands 12 can be simply layered andpressed into a desired shape to form seal 10.

In operation, seal 10 is installed on or in a tool and compressed toblock or restrict the passage of fluid therethrough. Seal 10 can be usedto isolate wellbore fluids, hold pressure, prevent sand production, orallow sufficiently small particles to pass through. Seal 10 may be usedto support cement or to plug a wellbore, for example, when the wellboreis to be plugged and abandoned. For sand retention, the weaving densityand setting force can be varied to produce the desired pore space inseal 10. By controlling the pore space and permeability of seal 10, afluid barrier may be obtained by creating a labyrinth effect or tortuouspath for fluid flow, thereby effectively preventing fluid communication.

Using various metals and/or other materials to weave or otherwise formseal 10, seal 10 can be used in various wellbore environments. Thoseenvironments include, but are not limited to, extremely low or hightemperature wellbores, or highly corrosive or relatively non-corrosivewellbore environments. Pressure holding requirements may vary from anabsolute seal to one in which fluid flow is merely restricted. Seal 10can be used in such widely differing applications by adjusting thesetting (compressive) force applied.

Depending on the shape and length of seal 10, seal 10 can be run throughsmall diameter openings (e.g., one inch) and set in a wide range ofouter diameters. For example, seal 10 may be run through tubing, but setin casing. Seal 10 can be used over many different casing sizes andweight ranges, thus reducing the number of designs required. Inaddition, seal 10 can be used in wellbore applications in whichimpairments exist in the casing that restrict access by standardoilfield tools.

Although only a few example embodiments of the present invention aredescribed in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exampleembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe following claims. It is the express intention of the applicant notto invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of theclaims herein, except for those in which the claim expressly uses thewords ‘means for’ together with an associated function.

1. A seal for use in a wellbore, comprising: a first tubular; a secondtubular; and a non-compressible tubular shaped body disposed between thefirst tubular and the second tubular, the body containing a plurality ofstrands disposed therein, wherein the strands are placed in anoverlapping arrangement to form a plurality of pores.
 2. The seal ofclaim 1 in which the strands are made of metal.
 3. The seal of claim 1in which the strands are made of a synthetic material.
 4. The seal ofclaim 1 in which the strands are woven.
 5. The seal of claim 4 in whichthe woven strands are woven in a helical pattern.
 6. The seal of claim 4in which the woven strands are woven in a circumferential pattern. 7.The seal of claim 4 in which the woven strands are woven in anorthogonal pattern.
 8. The seal of claim 1 in which the strands have acircular cross-section.
 9. The seal of claim 1 in which the strands havean angular cross-section.
 10. The seal of claim 1 in which the strandsare impregnated or coated with a conformable material.
 11. The seal ofclaim 1 in which the woven strands are made of natural materials. 12.The seal of claim 1 in which the woven strands are made of syntheticmaterials.
 13. The seal of claim 1 in which the woven strands comprise apolytetrafluoroethylene laminate.
 14. The seal in claim 1 in which thestrands are impregnated with an elastomer.
 15. The seal in claim 1 inwhich the strands are coated with an elastomer.
 16. The seal in claim 4in which the woven strands are impregnated with an elastomer.
 17. A sealfor use in a wellbore, comprising: a first tubular; a second tubular;and a non-compressible tubular shaped body disposed between the firsttubular and the second tubular, the body containing a fluid barrierdisposed therein, wherein the fluid barrier comprises a plurality ofpores that are sized to restrict passage of sand therethrough, but allowpassage of fluid, wherein the fluid barrier is a laminated, wovenfabric.